Bicycle drive assembly

Abstract

A bicycle drive assembly may include an axle, a hub shell rotatably mounted on the axle by a first bearing, a free hub rotatably mounted on the axle by a second bearing, and a ratchet mechanism releasably coupling the free hub to the hub shell to transmit torque from the free hub to the hub. The ratchet mechanism may include a first ratchet ring having an inner surface joined to the hub shell for rotation with the hub shell and a second ratchet ring having an inner surface joined to the free hub for rotation with the free hub. The first ratchet ring and the second ratchet ring encircle and radially overlap the first bearing and the second bearing, respectively. At least one spring resiliently biases the first ratchet face and the second ratchet face into engagement to transmit torque from the free hub to the hub shell.

What is claimed is: 
     
       1. A bicycle drive assembly comprising:
 an axle extending along an axis; 
 a hub shell rotatably mounted on the axle by a first bearing; 
 a free hub rotatably mounted on the axle by a second bearing; and 
 a ratchet mechanism releasably coupling the free hub to the hub shell to transmit torque from the free hub to the hub, the ratchet mechanism comprising: 
 a first ratchet ring joined to the hub shell for rotation with the hub shell, the first ratchet ring encircling and radially overlapping the first bearing, the first ratchet ring having a first axial ratchet face and an inner radial face interlocked to the hub shell to transmit torque between the first ratchet ring and the hub shell, wherein the axial face has a radial length RL and wherein the radial face has an axial length of at least 0.75 RL, wherein the first ratchet ring cross section has an L-shape; 
 a second ratchet ring joined to the free hub for rotation with the free hub, the second ratchet ring having a second ratchet face, the second ratchet ring encircling and radially overlapping the second bearing; and 
 at least one spring resiliently biasing the first ratchet face and the second ratchet face into engagement to transmit torque from the free hub to the hub shell, 
 wherein the first ratchet ring has a first leg of at least 3 mm and a second leg extending perpendicular to the first leg, the second leg having a length of at least 3 mm. 
 
     
     
       2. The bicycle drive assembly of  claim 1 , wherein the first leg has a ratchet toothed surface forming the first ratchet face and wherein the second leg has a splined surface and extends from the first leg in a direction towards the hub shell, the splined surface interlocking with the hub shell. 
     
     
       3. The bicycle drive assembly of  claim 2 , wherein the second ratchet ring has a first leg of at least 3 mm and a second leg extending perpendicular to the first leg, the second leg having a length of at least 3 mm. 
     
     
       4. The bicycle drive assembly of  claim 3 , wherein the first leg of the second ratchet ring has a ratchet toothed surface and wherein the second leg of the second ratchet ring has a splined surface interlocking with the free hub, the second leg extending from the first leg in a direction towards the free hub. 
     
     
       5. The bicycle drive assembly of  claim 1  further comprising an elastomeric damper axially captured between and engaging the second ratchet ring and the free hub. 
     
     
       6. The bicycle drive assembly of  claim 5 , wherein the elastomeric dampener seals against a portion of the free hub. 
     
     
       7. The bicycle drive assembly of  claim 5  further comprising a retainer secured to the hub shell and in engagement with the second ratchet ring to retain the second ratchet ring against the first ratchet ring upon separation of the free hub from the hub shell. 
     
     
       8. The bicycle drive assembly of  claim 7 , wherein the retainer comprises a C-clip partially received within an internal groove in the hub shell and projecting into engagement with an axial face of the second ratchet ring. 
     
     
       9. The bicycle drive assembly of  claim 1  further comprising a retainer secured to the hub shell and in engagement with the second ratchet ring to retain the second ratchet ring against the first ratchet ring upon separation of the free hub from the hub shell. 
     
     
       10. The bicycle drive assembly of  claim 9 , wherein the retainer comprises a C-clip partially received within an internal groove in the hub shell and projecting into engagement with an axial face of the second ratchet ring. 
     
     
       11. A bicycle drive assembly comprising:
 an axle extending along an axis; 
 a hub shell rotatably mounted on the axle by a first bearing; 
 a free hub rotatably mounted on the axle by a second bearing; and 
 a ratchet mechanism releasably coupling the free hub to the hub shell to transmit torque from the free hub to the hub shell, the ratchet mechanism comprising:
 a first ratchet ring joined to the hub shell for rotation with the hub shell, the first ratchet ring encircling and radially overlapping the first bearing, the first ratchet ring having a first ratchet face; 
 a second ratchet ring joined to the free hub for rotation with the free hub, the second ratchet ring encircling and radially overlapping the second bearing, the second ratchet ring having a second ratchet face; 
 at least one spring resiliently biasing the first ratchet face and the second ratchet face into engagement to transmit torque from the free hub to the hub shell; and 
 an elastomeric damper axially captured between and engaging the second ratchet ring and the free hub. 
 
 
     
     
       12. The bicycle drive assembly of  claim 11 , wherein the elastomeric dampener seals against a portion of the hub shell. 
     
     
       13. The bicycle drive assembly of  claim 11  further comprising a retainer secured to the hub shell and in engagement with the second ratchet ring to retain the second ratchet ring against the first ratchet ring upon separation of the free hub from the hub shell. 
     
     
       14. A bicycle drive assembly comprising:
 an axle extending along an axis; 
 a hub shell rotatably mounted on the axle by a first bearing; 
 a free hub rotatably mounted on the axle by a second bearing; and 
 a ratchet mechanism releasably coupling the free hub to the hub shell to transmit torque from the free hub to the hub, the ratchet mechanism comprising:
 a first ratchet ring joined to the hub shell for rotation with the hub shell, the first ratchet ring encircling and radially overlapping the first bearing, the first ratchet ring having a first ratchet face; 
 a second ratchet ring joined to the free hub for rotation with the free hub, the second ratchet ring encircling and radially overlapping the second bearing; 
 at least one spring resiliently biasing the first ratchet face and the second ratchet face into engagement to transmit torque from the free hub to the hub shell; and 
 a retainer secured to the hub shell and in engagement with the second ratchet ring to retain the second ratchet ring against the first ratchet ring upon separation of the free hub from the hub shell, wherein the retainer comprises a C-clip partially received within an internal groove in the hub shell and projecting into engagement with an axial face of the second ratchet ring.